<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Reference</title>
<style>
    .green {
        background-color: green;
        color: white;
    }
</style>
<body>
    <div class="green">This line should be green</div>
    <div class="green">This line should be green</div>
    <div class="green">This line should be green</div>
    <div class="green">This line should be green</div>
    <p class="green">This line should be green <em>and this should be green too</em></p>

    <div>This line should NOT be green</div>
    <div>This line should NOT be green</div>
    <div>This line should NOT be green</div>
    <div>This line should NOT be green</div>
    <div>This line should NOT be green</div>
    <div>This line should NOT be green<p>This line should NOT be green</p></div>
    <p>This line should NOT be green <em>and this should not be green either</em></p>
</body>
